The present invention relates to a molding system, and more particularly to a lock assembly for a low pressure mold assembly.
Many molding systems provide for the mixing of at least two fluid materials to form a hardenable or settable mixture which can be discharged into a mold cavity in the formation of an article molded of synthetic resin. One particular mixture includes three components, a catalyst, a matrix polymer and a foaming agent. The fluid materials are fed from a multiple of supplies by a delivery or feed assembly which communicates with a mixing head. All the fluid materials are mixed in the mixing head and discharged into the mold cavity to form the molded article.
In high production facilities problems can arise in connection with the opening and closing of molds. To achieve a tight joint the art had previously used various bolting systems or presses. However, such bolting systems are labor intensive and time consuming to use while the presses are rather large and complex. Moreover, if the bolts/nuts were not evenly tightened there could be uneven wear at the mold joint and/or instances of seepage at the joint. Similar seepage problems occur in the press-type systems if continued pressure is not applied thereto.
Accordingly, it is desirable to provide a lock assembly which provides a counter force to assure that the mold portions are proper and securely closed. It is further desirable to provide a lock assembly which is remotely activated such that the molds may be rapidly opened and closed in an assembly-line environment.
A low pressure mold assembly includes a first mold portion and a second mold portion which are selectively retained together by a lock assembly. In one embodiment, the lock assembly includes a male lock member mounted to the first mold portion and a female lock member mounted to the second mold portion. The male lock member is preferably a fixed pin which extends from the first mold portion to be received into the female lock member. The female lock member includes a movable lock plate having a key-hole shaped opening. An aperture through the second mold portion is sized to receive the outer diameter of the pin therethrough for engagement by the lock plate.
An actuator selectively moves the lock plate relative to the second mold portion between an unlocked and a locked position and to provide a counter force to the pressure within a filling mold. In the unlocked position, the relatively larger opening of the key-hole shaped opening is aligned with the aperture such that the pin is receivable through the second mold portion. In the locked position, the relatively smaller opening of the key-hole shaped opening is aligned with the aperture such that the lock plate captures the circumferential groove.
In another embodiment, the lock assembly includes a female lock member mounted to the first mold portion and a male lock member mounted to the second mold portion. The female lock member includes a fixed bracket having a pair of parallel plates each having a substantially hook-shaped opening. The male lock member includes a linear actuator to drive an engagement portion into the hook-shaped openings. A swing actuator drives the linear actuator through an arc such that the engagement portion of the linear actuator clears the female lock member for separation of the mold portions.
Accordingly, the present invention provides a lock assembly which provides a counter force assures the mold portions are proper and securely closed and are remotely activated such that the molds may be rapidly opened and closed in an assembly-line environment.